Overdrive control mechanism



g- 1960 E. E. PRATHER 2,947,192

OVERDRIVE CONTROL MECHANISM I Filed Oct. 23, 1957 O. D. SOLENOID 28 52 I 0.0. RELAY MADE AT 30 MRH.

44 ACTUATED 5 AT 60 M.P.H, OVERDRIVE TRANSMISSION RELEASED POSITION. I53 STAGE TRAVEL. 2"." STAGE TRAVEL;

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A TTORNE Y.

2,947,192 OVERDRIVE CONTROL MECHANISM Edwin E. Prather, Cassopolis, Mich, assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware 3 Filed Oct. 23, 1957, Sex. No. 691,970

5 Claims. 01. 14-472 This invention relates to automotive change speed transmissions in general and in particular to the overdrive type of transmission. 7

With the overdrive transmiss'ion'it is desirable that this mechanism be held in its overdrive setting when the automotive vehicle is traveling at a relatively high speed, say 60 m.p.h. or above; for with the vehicle traveling at such a high speed, the internal combustion engine thereof should not be speeded up sufiiciently to cooperate with the remaining parts of the driving means with the overdrive established in its underdrive setting; for the parts of the engine are probably not designed to stand up at such a speed; furthermore, the torque developed by the engine at this 60 m.p.h; or more speed makes a downshift of the transmission undesirable.

It is accordingly an important object of my invention to provide a control for the overdrive mechanism which will be automatically cut out of operation when the vehicle reaches a speed of say, 60 m.p.h.

A further object of my invention is to provide control means for an overdrive mechanism which will be operative to effect a kickdown, that is downshift, operation of the mechanism when the throttle is opened relatively Wide and despite a certain failure of one of the switches of the control means. i

Other objects of the invention and desirable details of construction of parts will become apparent from the following detailed description of an illustrative embodiment of the invention, taken in conjunction with the accompanying drawings illustrating said embodiment, in which:

Figure 1 is an electrical schematic view disclosing the principal features of the control means of my invention;

Figure 2 is a top plan view of the two-stage governor of my invention; and V Figure 3 is a sectional View, taken on the line 3--3 of Figure 2, disclosing the details of the governor of my invention.

Referring now to Figure 1 disclosing a preferred embodiment of my invention, the reference numeral 10 indicates the combination overdrive solenoid and switch unit in use on many of the cars of the day, said unit constituting a part of the control means of my invention. This unit includes a solenoid 12 comprising a grounded coil 14 and an armature 16. This coil and associated parts of the unit 10 are shown in their off position, the coil being deenergized. A stem portion 18 of the armature serves to actuate the pawl of the transmission overdrive mechanism, not shown, said pawl, when the solenoid is energized, serving to actuate said mechanism to place the same in its overdrive setting. 'When. the solenoidis energized, the armature and its stem move downward thereby compressing a return spring 20 said spring being positioned betweena stop 22 and a portion of the armature, all as is disclosed in Figure 1; and with'thc downward'movement of the armature, a grounded switch 24, biased to its closed position by 'a spring 26, is closed. When the solenoid 12 is de-energized, the spring 20, stronger than the spring 26, expands to open the switch 24, apin 27 senited States, Patent 0- cured to the armature 16 serving to move a switch arm 29 upward.

The overdrive solenoid unit 10 iscontrolled by a relay 28 comprising a coil 30 and a normally open switch 32. In this relay the switch 32 thereof is wired in series with the ignition switch 34 of the car, a grounded battery 36 and the grounded coil 14 of the overdrive unit; and the coil 3t) of the relay is wired in series with the grounded battery, the ignition switch, an overdrive lockout switch 38, a governor operated normally open switch 40, and one of the two switches of an accelerator operated doublepole double-throw kickdown switch 42. This switch is indicated by the reference numeral 44 and is grounded. The remaining switch of this-two-part kickdown switch mechanism is indicated by the reference numeral 46 and is electrically connected in series with the grounded switch 24 of the overdrive unit, a governor operated normally closed switch 48 and the primary winding of the ignition coil 50 of the ignition system of the vehicle. When this primary winding is grounded the ignition system is disabled thereby rendering the internal combustion of the vehicle inoperative.

It is necessary to momentarily disable the engine, that is reverse the torque, in order to operate the overdrive mechanism of the vehicle; and this is done, with the mechanism of my invention, either by releasing the alccelerator to effect the upshift operation ofthe overdrive or by momentarily disabling the ignition system to effect the downshift or so-called kickdown operation of the overdrive. The switches 40 and 48 are operated by a two-stage governor indicated as a whole by the reference numeral 52 in Figures 2 and 3. This governor mechanism is disclosed in detail in the latter figures and constitutes an important part of my invention.

Referring now to'Figures 2 and 3 disclosing the governor, this mechanism includes a plate 56 rectangular in outline. Pin supporting end plates 58 are secured to the plate 56 and together with said plate form a centrifugal weight supporting channel member. As is disclosed in Figure 3, the plate 56 is fixedly mounted on a drive shaft 60 which may be connected to the propeller shaft of the vehicle or any other moving part of the vehicle the speed of which is directly proportional to the speed of the vehicle. Prism shaped centrifugal weights A, four in number, are pivotally mounted within the channel member 56, 53 on pins 62 which are mounted, at their ends, in the end plates 58; and as is disclosed in Figure 2, prism shaped centrifugal weights B, two in number are pivotally mounted on the pins 62 and are positioned between the weights A. All of the weights are notched to receive a rectangular shaped plate 64 positioned within the channel member, said .plate having fixedly secured thereto a cylindrically shaped'switch operating pin 66. This pin is hollowed out to receive'a guide pin 68 mounted on the end of the drive shaft 60. The four weights A are provided with a bevel portion 70 outlining, with the plate 56, an angle of say 10; and the two weights B are beveled at 72 to outline, with the plate 56, an angle of say 20 Describing the operation of the governor mechanism 52, when the vehicle is traveling at say 30 m.p.h. the six centrifugal weights A and B operate in unison to move the plate 64 and its pin 66 upwardly to their first-stage travel position which is indicated in dotted :lines in Figure 3; and by this operation the pin 66 serves to actuate the switch 40, Figure 1, to close the same; When the vehicle reaches a speed of say 60 m.p.h. the two weights B are operative in unison to move the pin 66 to its second-stage portion 70 of the weights A moves into contact with the plate 56 when the speed is 30 m.p.h.; accordingly, above this speed there is no further pin operating movement of the weights A. It is to be noted that the notch in the weights A is deeper than the notch in the weights B this being necessary to permit the continued movement of the pin 66 when the vehicle speed is increased above 30 m.p.h. The switches 40, 48 and '74 are not disclosed in Figure 3 inasmuch as any suitable connection may be provided between the pin 66 and said switches.

As to the operation of the control mechanism of my invention the driver may, with the lockout switch 38 and the kickdown switch 44 closed, effect an overdrive setting or the transmission by speeding the vehicle up to 30 m.p.h. thereby closing the switch 40, and then releasing'the accelerator to reverse the engine torque; and he may thereafter, provided the vehicle is traveling under 60 m.p.h. kickdown, that is downshift the transmission, by depressing the accelerator sufiiciently to open the switch 44 and close the switch 46; for, as will be noted from an inspection of the wiring of Figure 1, opening the switch 44 results in a de-energization of the solenoid l4, and a closing of the switch 46 results in a grounding of the coil 50 to reverse the engine torque. This reversal of the engine torque is however only momentary inasmuch as an expansion of the spring 20 to operate the overdrive results in an opening of the switch 24 to restore the ignition. At a vehicle speed of 60 m.p.h. the switch 74 is automatically closed and the switch 48 opened thereby preventing a kickdown operation of the transmission so long as the vehicle is traveling at or above such a speed. Accordingly the mechanism of Figure 1 protects the engine from the bad efiects of the high engine speed operation which would result if the mechanism permitted a downshift setting of the transmission when the vehicle is traveling at or above 60 m.p.h. The mechanism of Figure 1 also insures a starting of the engine despite an untoward closing of the switch 24 by a deposit of electrically conductive foreign material lodged between the contacts of said switch. And with the mechanism of my invention the energization of the solenoid 14 at or above 30 m.p.h. to a degree prevents an unwanted downshift operation of the transmission which might otherwise result if the car is severely jolted by striking a rut in the road; for with such an operation the stem portion 18 of the solenoid is held downwardly to maintain the gear setting despite such a severe jolting of the car.

There is thus provided, by my invention, an efficient and elfiective control means for an automotive overdrive transmission mechanism, said control means, in addition to effecting a normal operation of the overdrive, being operable to prevent a kickdown operation of this mechanism when the vehicle is traveling above a relatively high speed; and also operable to insure both a normal kickdown operation of the overdrive and a starting of the engine of the vehicle despite an undesired closing, as by the operation of foreign matter, of the overdrive solenoid operated switch of the control.

While one embodiment of the invention has been described in considerable detail, I do not wish to be limited to the particular construction shown which may be varied within the scope of the invention, and it is the intention to cover hereby all adaptations, modifications and arrangements thereof which come within the practice of those skilled in the art to which the invention relates.

I claim:

1. In an automotive vehicle provided with a grounded battery, an accelerator, an ignition system including an ignition coil, and an overdrive transmission including a pawl member and capable of being established in one or" the other of two settings; means for controlling the operation of the transmission including a solenoid comprising 'a grounded coil and an armature, a normally closedzg'rounded switch actuated by the armature, means including an interconnecting the grounded switch and armature, means interconnecting the armature and pawl of the transmission, means electrically interconnecting the ignition coil and switch to provide a means for temporarily disabling the ignition system to facilitate one of the operations of the transmission said connecting means including a normally closed governor operated switch, means electrically interconnecting the battery and coil of the solenoid including a normally open relay switch, and electrical means for controlling the operation of the relay switch including a relay coil and further including means for controlling the flow of electricity through said coil accelerator operated kickdown switch, a plurality of governor operated switches one of which is closed when the vehicle is traveling at a relatively high speed, and a two-stage governor for operating the governor operated switches.

2. An electrical control circuit for an engine driven two speed transmission and the like wherein the transmission of a vehicle is controlled by mechanism having normal and second conditions, and which mechanism is caused to be held in its second condition until vehicle retarding torque is supplied by the engine, said circuit comprising: an electrical solenoid which when in one of its energized and nonenergized conditions urges said mechanism into its second condition, said mechanism thereafter being held in its second condition even though said solenoid is placed in its other normal condition, an electrical control circuit for said solenoid, said circuit including first and second governor operated switch portions and a first kickdown switch portion each portion having normal and actuated conditions, said control circuit being arranged so that said solenoid is in its second condition when said first governor operated switch portion is in its actuated condition and said first kickdown switch portion is in its normal condition or said second governor switch portion is in its actuated condition, and said solenoid being in its normal condition when said first governor switch portion is in its normal condition, or said first governor switch portion and said first kickdown switch portions are in the actuated conditions; an engine interrupter circuit including a third governor switch portion and a second kickdown switch portion each of which have normal and actuated conditions, said interrupter circuit allowing said engine to provide reverse torque on said transmission when said third governor switch portion is in its normal condition and said second kickdown switch portion is in its actuated condition, said interrupter circuit being prevented from causing said reverse torque when said third governor switch portion is in its actuated condition; and a three condition governor structure which causes said first governor switch portion to be actuated at a first vehicle speed, and which causes said second and third governor switch portions to be actuated at a higher second vehicle speed.

3. An electrical control circuit for an engine driven two speed transmission and the like wherein the transmission of a vehicle is controlled by mechanism having normal and secondconditions, and which mechanism is caused to be held in its second condition until vehicle retarding torque is supplied by-the engine, said circuit comprising: an electrical solenoid which when in one of its energized and nonenergized conditions urges said mechanism into its second condition, said mechanism thereafter being held in its second condition even though said solenoid is placed in its other normal condition, an electrical control circuit which places said solenoid in its normal condition when said circuit is de-energized, said circuit including normally open first and second governor switch portions and a normally closed first kickdown switch portion, said first switch portions being in series circuit and said second governor switch portion and said first kickdown switch portionbeing in parallel circuit; an engine interrupter circuit which caused said reverse torque when energized and including a normally closed third .governor switch portion,

and a normally open second kickdown switch portion; and a three condition governor structure which causes said first governor switch portion to be closed at a first vehicle speed, and which causes said second governor switch portion to be closed and said third governor switch portion opened at a higher second vehicle speed.

4. An electrical control circuit for an engine driven two speed transmission and the like wherein the transmission of a vehicle is controlled by mechanism having normal and second conditions, and which mechanism is caused to be held in its second condition until vehicle retarding torque is supplied by the engine, said circuit comprising: an electrical solenoid which when in its energized condition urges said mechanism into its second condition, said mechanism thereafter being held in its second condition even though said solenoid is placed in its other normal condition, an electrical control circuit which places said solenoid in its de-energized condition when said circuit is de-energized, said circuit including normally open first and second governor switch portions and a normally closed first kickdown switch portion, said first switch portions being in series circuit and said second governor switch portion and said first kickdown switch portion being in parallel circuit; an engine interrupter circuit which caused said reverse torque when energized and including a normally closed third governor switch portion, and a normally open second kickdown switch portion; and a three condition governor structure which causes said first governor switch portion to be closed at a first vehicle speed, and which causes said second governor switch portion to be closed and said third governor switch portion opened at a higher second vehicle speed.

5. An electrical control circuit for an engine driven two speed transmission and the like wherein the transmission of a vehicle is controlled by mechanism having normal and second conditions, and which mechanism is caused to be held in its second condition until vehicle retarding torque is supplied by the engine, said circuit comprising: an electrical solenoid which when in its energized condition urges said mechanism into its second condition, said mechanism thereafter being held in its second condition even though said solenoid is placed in its other normal condition, an electrical control circuit which places said solenoid in its de-energized condition when said circuit is deenergized, said circuit including normally open first and second governor switch portions and a normally closed first kickdown switch portion, said first switch portions being in series circuit and said second governor switch portion and said first kickdown switch portion being in parallel circuit; an engine interrupter circuit which caused said reverse torque when energized and including a normally closed third governor switch portion, a normally open second kickdown switch portion, and a normally open switch which is closed when said transmission is in its second condition, and a three condition governor structure which causes said first governor switch portion to be closed at a first vehicle speed, and which causes said second governor switch portion to be closed and said third governor switch portion opened at a higher second vehicle speed.

References (liter! in the file of this patent UNITED STATES PATENTS 2,306,865 Claytor Dec. 29, 1942 2,317,423 Vincent Apr. 27, 1943 2,319,746 Orr May 18, 1943 2,328,291 Osbourne Aug. 31, 1943 2,409,541 Carnagua Oct. 15, 1946 2,585,437 Claytor Feb. 12, 1952 2,598,184 Long May 27, 1952 2,732,834 Morgan Jan. 31, 1956 

